Thermal imaging cameras are used in a variety of situations. For example, thermal imaging cameras are often used during maintenance inspections to thermally inspect equipment. Such equipment may include rotating machinery, electrical panels, or rows of circuit breakers, among other types of equipment. Thermal inspections can detect equipment hot spots such as overheating machinery or electrical components, helping to ensure timely repair or replacement of the overheating equipment before a more significant problem develops.
Depending on the configuration of the camera, the thermal imaging camera may also generate a visible light image of the same object. The camera may display the infrared image and the visible light image in a coordinated manner, for example, to help an operator interpret the thermal image generated by the thermal imaging camera. Unlike visible light images which generally provide good contrast between different objects, it is often difficult to recognize and distinguish different features in a thermal image as compared to the real-world scene. For this reason, an operator may rely on a visible light image to help interpret and focus the thermal image.
In applications where a thermal imaging camera is configured to generate both a thermal image and a visual light image, the camera may include two separate sets of optics: visible light optics that focus visible light on a visible light sensor for generating the visible light image, and infrared optics that focus infrared radiation on an infrared sensor for generating the infrared optics. Appropriately configuring each of these sets of optics may dictate the ease with which an operator can use the thermal imaging camera and the quality of the visible light and infrared images generated by the thermal imaging camera.
In some situations, it can be difficult to detect a change in temperature using a thermal imaging camera by visual observation of the live image or saved infrared images. For example, if an object normally operates at an elevated temperature, an increase in temperature of the already hot object may be hard to detect. Alternatively, if the change in temperature occurs slowly over a period of time, or if the temperature change only occurs intermittently, it may also be difficult to notice a change in a thermal image only by visual observation of the image. In such situations, it would be useful to have a better way to monitor and detect temperature changes over time using a thermal imaging camera. In addition, some parameters that are available only in numeric form on the live image, like minimum or maximum temperatures, or center box average temperatures are not easily monitored for changes over time by the human eye.